1. Technical Field
This invention generally relates to electric fireplace assemblies. More particularly, the invention relates to a reflective device for use in an electric fireplace assembly for varying the light therein so as to aid in simulating natural looking flames. Specifically, the invention relates to a reflective device and a fireplace incorporating the same where the device includes a plurality of relatively thin reflecting strips extending longitudinally between first and second end caps mounted on the ends of a rotatable shaft.
2. Background Information
Electric fireplaces have grown in popularity over recent years. One of the major hurdles that a manufacturer of such fireplaces has to overcome, is the simulation of realistic looking flames. If the simulated flames do not rise and fall and change in light intensity, then those flames appear unnatural. This leads to an aesthetically less appealing fireplace.
A number of patents have been issued for electric fireplaces and many of these patents include different mechanisms for simulating flames and for generating a flickering effect. Typically, the flickering light effect is created by incorporating a device that reflects light from a light source onto a translucent screen that is positioned rearwardly of an artificial log display and/or simulated ember bed. The reflective devices known in the prior art fall generally into three different categories. A first group of reflective devices disclosed in the prior art comprises vertically oriented ribbons or strips of reflective material. These reflective ribbons are spaced horizontally apart from each other and are subjected to some type of airflow that creates movement in the ribbon and thereby varies the light reflected therefrom. One example of a patent that discloses this type of reflective device is U.S. Pat. No. 4,965,707 issued to Butterfield, The Butterfield device includes a plurality of light-reflecting ribbons that are each cut in the shape of a flame and are individually suspended from a horizontally oriented anchor rod by a thread. A second end of each flame-shaped ribbon is secured to a second horizontally oriented anchor rod by a pin. The ribbons may be pre-twisted or suspended with an edge adjacent the screen. A breeze is generated by a fan and the ribbons twist and flutter in the breeze. Each ribbon has a reflective surface and the fluttering causes light to be reflected from the ribbons in a varied pattern.
Chinese Patent CN1416518A (Gerrard) discloses a plurality of reflective ribbons that are each connected at one end to a horizontal surface and are free at the opposite end. A fan blows air onto the ribbons and causes them to flutter and thereby reflect light shone onto the ribbons in a scattered, flickering manner.
A second group of patents disclose reflective devices which comprise some type of reflective cylinder having a pattern of apertures cut into its exterior wall. A light source is disposed in the interior of the cylinder and shines outwardly therefrom through the apertures and onto the screen. Alternatively, a light source is positioned outside of the cylinder but in such a location that light will shine through the apertures in the cylinder wall and onto the screen. The rotation of the cylinder causes interruptions in the steam of light shining onto the screen and in this manner generates a flickering effect of the light. An example of a patent that includes this type of reflective cylinder is U.S. Pat. No. 7,236,693 (Haugom). Haugom discloses a flame simulating apparatus which includes a hollow cylinder rotatable about its axis. The cylinder is mounted horizontally proximate a translucent screen in the fireplace housing and includes a sidewall with a plurality of apertures therein. The apertures are generally vertically oriented and are curvilinear in shape. A light source is disposed in the interior of the cylinder and, when activated, light is transmitted through the apertures and falls onto the back surface of the screen.
Martin (U.S. Pat. Nos. 6,393,207 and 6,757,487) also discloses a flame simulation assembly that includes a rotating hollow cylinder having a plurality of shaped openings in its outer wall. In Martin's devices the cylinder has a highly reflective interior surface. Light from the light source is transmitted into the interior of the cylinder through the openings, is reflected off the interior surface and is transmitted outwardly from the cylinder through other openings and onto the diffuser screen.
Chen (U.S. Pat. No. 7,322,136) discloses a flame simulation assembly which includes a fixed light source centered in a cover having a plurality of blades mounted between two sidewalls and separated from each other by horizontally oriented gaps. The blades have a plurality of flame-shaped apertures cut into them. Colored “flicking” boards are mounted exteriorly of the blades and rotate therewith. The blades and flicking boards rotate around the light source and light shines outwardly from the cover through the horizontal gaps, through the flame-shaped apertures and onto the screen. Preferably, the blades are curved and the curvature is such that the blades are eccentric relative to the axis of the light source. This supposedly enhances the natural looking appearance of the flickering light.
U.S. Publication Nos. 2008/0181587 (Patil et al) and 2008/0181588 (Gorby) disclose cylinders with apertures in the exterior wall and through which light shines onto a diffusion screen. Chiu (US Publication No. 2009/0080871) discloses a cylinder with apertures in its external wall and having a plurality of LED light sources disposed in the interior of the cylinder.
A third group of reflective devices disclosed in the prior art includes those comprising a shaft that is rotatable about its axis and having a plurality of reflective fingers, filaments or surfaces secured to the shaft and extending radially outwardly away therefrom. This is by far the biggest group of reflective devices disclosed in the art. Examples of patents that include this type of reflective device include U.S. Pat. Nos. 6,944,982 and 7,080,472 to Schroeter et al. These references disclose a light reflective device comprising a rotatable shaft with a plurality of light reflecting fingers extending outwardly therefrom in a variety of different directions relative to each other. The fingers are generally curved in shape and originate and terminate in the circumferential surface of the shaft.
Berry (GB 1,164,143) discloses a reflective device in which a number of jagged or saw-tooth vanes extend radially outwardly from a central shaft.
Dimplex North America Limited has a number of patents and patent applications assigned to it by the inventors Hess, Hess et al and MacPherson et al. Each of these references discloses the use of a rotatable shaft having a number of reflective fingers secured at one end to the shaft and extending generally radially outwardly therefrom. These patents and applications include U.S. Pat. Nos. 5,642,580; 6,047,489; 6,269,567; 6,363,636; 6,385,881; 6,564,485; 6,615,519; 7,134,229, 7,162,820, 7,194,830; 7,373,743; 2002/0139021; 2003/0110671; and 2004/0181983.
Additionally, U.S. Pat. No. 3,499,239 (Mungo), U.S. Pat. No. 4,890,600 (Meyers), and Painton (U.S. Pat. No. 3,699,697) and US Publications Nos. 2009/0126241 (Asofsky) and 2009/0220221 (Zhou) each disclose a central shaft having a plurality of reflective surface extending radially outwardly away from the circumferential surface of the shaft.
A number of foreign patents, applications and utility models also show this type of reflective device including CN2767211 (Zhu Hongfeng); CN2424392Y (Chen Xiaoliang), CN2847438Y (Lin Congbao), CN2888579Y (Zhou Jun), CN2874697Y (Zhu Hongfeng), CN2828998Y (Zhu Hongfeng), CN2637956Y (Yang Wei), CN26191781Y (Yang Wei) and CN2511902Y (Ying Jianqiang).
While all of these reflective devices produce variations in light shining on the screen behind the artificial logs, there is still room in the art for an improved reflective device that aids in creating lighting that simulates a more natural looking flame effect.